@article{Grohe_1997,
    doi = {10.1093/logcom/7.2.205},
    url = {https://doi.org/10.1093%2Flogcom%2F7.2.205},
    year = {1997},
    month = {apr},
    publisher = {Oxford University Press ({OUP})},
    volume = {7},
    number = {2},
    pages = {205--228},
    author = {M Grohe},
    title = {Existential least fixed-point logic and its relatives},
    journal = {Journal of Logic and Computation}
}

@article{Grohe_1997, doi = {10.1093/logcom/7.2.205}, url = {https://doi.org/10.1093%2Flogcom%2F7.2.205}, year = {1997}, month = {apr}, publisher = {Oxford University Press ({OUP})}, volume = {7}, number = {2}, pages = {205--228}, author = {M Grohe}, title = {Existential least fixed-point logic and its relatives}, journal = {Journal of Logic and Computation} }